Which primitives does LaTeX2e rename/move?

Question

TeX's primitives can be renamed by macro formats/packages: this allows new/altered features or behaviours. Usually this is done such that the originals are still available ('renamed'): certainly ConTeXt does this (for example \normalend). Which primitives does the LaTeX2e kernel move/rename?

Answer 1

The LaTeX kernel (latex.ltx) saves a few primitives with new names: these are all from TeX90 as the kernel itself does not absolutely require primitives from e-TeX or later. Two of these are token registers, saved as \frozen@...:

• \everydisplay saved as \frozen@everydisplay
• \everymath saved as \frozen@everymath

The other 'renamed' primitives are all saved as \@@...:

• \- saved as \@@hyph
• \/ saved as \@@italiccorr
• \end saved as \@@end
• \input saved as \@@input
• \par saved as \@@par (note that \par is still the primitive in the preamble)
• \underline saved as \@@underline
• \shipout saved as \@@shipout (but used by the kernel as simply \shipout: the saved primitive is to allow for packages that need to get to the raw behaviour irrespective of other loaded material)